Sound transmission reduction structures



y 1933. R, s. PHILLIPS SOUND TRANSMISSION REDUCTION STRUCTURES Filed Oct. '7, 193

Patented May 16, 1933 UNITED STATES PATENT OFFICE ROBERT S. PHILLIPS, OF OAK PARK, ILLINOIS, ASSIGNOR T AMERICAN HAIR & FELT COMPANY, A CORPORATIQN OF DELAWARE SOUND TRANSMISSION REDUCTION STRUCTURES Application filed lictober 7,

nomically, be of reduced thickness, with consequent reduction in the amount of material required, and present greater obstruction to sound transmission than structures as hitherto provided.

Referring to the accompanying drawing: Figure 1 is a broken perspective view of a structure for reducing sound transmission and constituting one ofthe embodiments of my invention.

Figure 2 is an enlarged, broken, view in vertical sectional elevation of the structure shown in Fig. 1, and

1 Figure 3 is a broken, perspective, view of a wall construction in which the structure of Figs. 1 and 2 is installed,

The structure shown in Figs. 1 and 2, and in Fig. 3 as installed in a wall construction, and which is in the form of a blanket, and is represented generally at :v, comprises several layers 5 of paper, or the like coated throughout the areas. of their opposite sides, as represented at 6, with a tacky material such as asphalt preferably of such consistency as to .remain'slightly viscous under the temperature'to which thest'ructure is. subjected in use. The several layers 5 are spaced apart as showmand the spaces tlierebetween filled with masses 710i fibrous material such as that above referred' to, which become ad- I hered to the tacky The masses 7 of fibrous material are eachshown as havingm, core 8 of upae, orthe like, coextensive with "the areas of the layers 5, but,'-as shown,

spaced therefrom, the core 8 having punched the'rethrough, by n d at close int-"185 as for exampleaboutoneseighth of an inch,

and over their entire 'areas, portion of the fibers forming the masses 7 thereof,thereby 195%. Serial No. 487,0??8.

producing what is commonly known as paper-core punched 'felt.

In Fig. 31 have shown one of the situations in which the sound-transmission-reducing structure of Figs. 1 and 2 may be used and the preferred way in which it is installed. In this arrangement the soundtransmission-reducing structure is applied between adjacent studding 9 of a wall or partition structure, to the inner sides of the laths 10 at intervals and is engaged by crosspieces, or slats, 11 located between the studoling 9 and forced against the sound-transmission-reducing structure as shown to compress the latterand in such position secured to the studding, the upper one of the slats being shown by dotted lines to permit of the showing of the way the sound-transmission-reducing structureisdeformed by this slat when'applied as stated. r

While both paper sheets and masses of fibrous material disassociated with each other, possess the property of reducing sound transmission the assembling of these elements in layers into a structure disposed normal to the path of sound waves, results in the reduction of sound transmission to a degree greater than the sum of the effectiveness of these materials separately used; and I have availed myself of this condition and provided a structure of relatively inexpensive construction in the provision of the structures as shown. It is my aim to reduce to as great a degree as possible vibrations in the sheets of paper produced responsive to theaction of the sound waves thereon, thereby commensurately reducing sound transmission.

The compressive forces of the fibrous mass thereof against the paper layers act as elastic cushions over theentire area of the paper and thus reduce vibrations in the latter. The damping action just referred to is further augmented in the constructions shown by the provision of the tacky coatin of the .paper sheets inasmuch as certain o thefibers-of the masses thereof and arranged till) addition to the compressive forces exerted aglainst the paper and above referred to. T e placing of certain of the fibers of the 'mass thereof under tension as stated results from the mere fact of adherence of the fibers of the mass to the tacky coating. Furthermore, the production of tensile stresses in the fibers producing tensile forces in the paper to damp vibrations-ma be, and in the constructions shown are, e ected by the provision of the paper-corepunched felt above referred to, certain of the fibers of which, in being unched through the core, being placed un er tension an acting directly upon the paper by the friction contact of the fibers with the paper core at the perforations therein.

' ture, provided as a blanket as sta is made either of such dimensionsas to cover the area to be provided with the sound-trans- It is desirable that the fiber mass or masses, as the case may be, be under relatively great compression for subjectin the paper to relatively great compressive orces exerted against it by those of the fibers which are under compression, as the degree of damping by such forces is dependent on the strength of such forces. In the construction shown in Figs. 1--3 this condition of. augmented compression is effected by associating the sound-reducing structure with slats as above explained.

It will furthermore be noted that paper coated as stated will not vibrate as freely as uncoated (paper and thus its ability to transmlt soun is greatly reduced as compared with uncoated paper. The fact that there is an imperforate layer between the layers of felted fibers is important, as the presence of perforations through the layers of paper would provide an air connection between the entrained ,air in each of the felt layers, and air is a good conductor of sound vibratiohs.

The sound-transmission-reducin strucmay be mission-reducing structure, or in the form of a continuous sheet which may be cut to provide the section of the desired-dimensions.

imperforate sheets of paper, and loosely Vassembled fibrous bodies located in the spaces between said sheets, the surfaces of said spaced from the adjacent sheets, and loosely assembled fibrous bodies located in the spaces between said. sheets, the surfaces of said sheets opposed to said fibrous material being coated with a rmanently tack material to which fibers 0 said mass are a hered.

3. A sound-transmission-reducin structure comprising a plurality of imperiorate sheets of paper each spaced from the adjacent sheets, masses of cushioning material filling the spaces between said sheets, said masses each comprisin a layer of loosely assembled fibers pricke through a layer of reinforcin paper, the surfaces of said imperforate s eet opposed to said cushioning masses being coated with tacky material to which the fibers of said masses are adhered.

' ROBERT PHILLIPS.

While I have illustrated and described certain particular embodiments of my invention, I do not wish to'be understood as intendingtof limit it thereto as the same may be variously modified an altered without departing from the spirit ofmy invention. urthermore, the structures as shown incorporatetherein in combination, the various features which I regard as novel.

' However, these features may be separately, or in various combinations, embodied m structures without departing from the spirit of my invention; i What I claim as new, and desire to secure by Letters Patent, is:

1. A. sound-transmission-reducing structure comprising a plurality of spaced apart, 

